[Problem] To provide a chemical reaction device in which, in the interior of a reactor, the concentration of microwaves in one portion can be reduced, and microwaves are caused to more evenly radiate onto contents. [Solution] A chemical reaction device (1) comprises: a horizontal flow-type reactor (13) in which liquid contents flow horizontally in a state where there is an unfilled space thereabove; a microwave generator (14) for generating microwaves; and a waveguide tube (15) for transmitting microwaves generated by the microwave generator (14) into the unfilled space of the reactor (13). The upper side of the reactor (13) has a curved shape relative to the direction of flow of the contents.
